The space shuttle Atlantis blasted off Friday morning on the historic final flight of NASAÃ¢ÂÂs 30-year shuttle program.

The shuttle was in its preliminary orbit around the Earth 10 minutes after what NASA called a "flawless launch" at 11:29 a.m. ET. That was three minutes after its scheduled launch time of 11:26 a.m. ET, despite a forecast calling for a 70 per cent chance of thunderstorms that the U.S. space agency feared could delay the launch.

"With today's final launch of the space shuttle, we turn the page on a remarkable period in America's history in space, while beginning the next chapter in our nation's extraordinary story of exploration," said NASA administrator Charles Bolden in a statement following the launch.

"Tomorrow's destinations will inspire new generations of explorers, and the shuttle pioneers have made the next chapter of humanspace flight possible."

Atlantis carries NASA astronauts Chris Ferguson, the mission commander, shuttle pilot Doug Hurley, and mission specialists Rex Walheim and Sandy Magnus. They are scheduled to dock at the International Space Station at 11:06 a.m. ET Sunday.

As many as a million people were estimated to be gathered at or near the space centre to watch.

"Everybody who isn't watching the royal couple this morning is driving here to watch us launch," Canadian astronaut Col. Chris Hadfield told CBC News from the Kennedy Space Center in Florida.

The weather has been hot and humid, and Thursday a lightning strike within 150 metres of the launching pad prompted NASA to convene an engineering panel to discuss any possible damage.

'It's almost poetic in [its] beauty Ã¢ÂÂ¦ this great gleaming human icon, this human arrow that takes us to space.'Ã¢ÂÂ"Chris Hadfield, Canadian astronaut

"There's a huge lightning rod on top of the pad, of course, but if any stray electricity comes through the shuttle systems or the rocket there's a chance something could short out or something could be compromised," he said.

"So when we get a lightning hit we have to go through and check everything."

Day for nostalgia

This is an emotional day for people close to the space program. Hadfield said he and a group of guests and family members viewed Atlantis up close, high on the launch pad, just after sunset Thursday.

"It's almost poetic in [its] beauty Ã¢ÂÂ¦ this great gleaming human icon, this human arrow that takes us to space," he said.

Hadfield said that despite the retirement of the shuttle, space flight has never been busier, with frequent flights to the International Space Station aboard Russian spacecraft and new vehicles on the drawing board.

"It's a busy time to be an astronaut," he said.

The send-off for the 135th shuttle launch is also special to the die-hard space program fans in their tents and camper vans along the Florida coast, who are paying tribute to a shuttle program that helped build the space station, fixed the Hubble telescope and sent probes to the planets.

"You spend two days coming down to look at it and it's over in 30 seconds," said retiree Eddie Wilson, who drove in from Atlanta. "But it is something about seeing that vehicle and the massive propulsion system to boost into to space. And to know that people are riding up into space on that."

Atlantis carries a year's worth of supplies Ã¢ÂÂ" more than 8,000 pounds Ã¢ÂÂ" for the International Space Station. It will also bring up a system that will be used by Canada's Dextre robot to test a system for refuelling and repairing spacecraft and satellites in space. When it returns, it will bring back to Earth a failed ammonia pump module to help NASA better understand what caused the pump to stop working.

Following the 12-day mission, Atlantis will go on display at the Kennedy Space Centre. The two other retired shuttles are heading to museums in Los Angeles and Virginia.